Slush pump piston and piston rod



' sLJsH PUMP PIs'roN AND vPIsToN aon Filed on, :5, 1947 2:4 2 -33 l2 34 so f/f /3 INVEN TOR. ko/65 C 'WELLS 6r /l/.s Arron/V575 ww( M Patented June 3, 19 52 SLUSH PUMP PISTON AND PISTON ROD George C. Wells, Lomita, Calif., assignor to Neal H. Anderson Oil Tool Co., Torrance, Calif., a partnership composed of Neal H. Anderson and George C. Wells Application October 3, 1947, Serial No. 777,747V

(Cl. 30S- 4) 20 Claims.

l This invention relates to pumps, particularly to those known as slush pumps, and more especially to piston and piston rod constructions therefor.

Slush pumps of the indicated character arel commonly employed in the pumping of so-called drilling mud used in the drilling of deep Wells, such as oil wells. As modern drilling practices have developed oil and gas wells have become deeper and deeper, and the loads imposed upon slush pumps in circulating drilling mud under steadily increasing hydraulic heads have become greater and greater. As a consequence, it has become impossible in a great many instances to retain the pistons on the piston rods by the means and methods conventionally employed, as illustrated by threaded retaining nuts mounted upon the ends of the piston rods. Such piston rod ends are commonly slender and permit stretch. In addition, the shock loads which are applied during reciprocating operation to the threads by which the nuts are ailixed cause loosening by wear at the threads and at the engaging faces between the nuts and the pistons. The severity of these loads is apparent when it is realized that in the drilling of deep Wells steam pressures in the order of 350 to 500 pounds are now common as against earlier requirements of 100 pounds and less. Also, pump diameters have been increased from about 12 inches to about 20 inches, thus further greatly increasing total loads imposed, which may run up to a possible maximum of 120,000 pounds.

Another factor involved in the circulating of drilling mud in deep well drilling is found in the fact that as greater depths'are reached in the drilling of the well, more circulating power is required. Since the power of the prime mover cannot ordinarily be appreciably increased, the cross sectional area of the pistons is decreased, and liners of smaller internal diameter are successively employed to replace liners of larger internal diameters. Such liner substitutions require correspondingly smaller piston diameters.

In View of the diniculties above outlined, it is one object of this invention to provide a piston and piston rod construction capable of withstanding the increasing shock loads currently imposed upon slush pump pistons and their rods, an incidental object being to avoid loosening of the pistons on their rods and to avoid detachment of the pistons from their rods because of thread wear or stripping.

Another object of the invention is to provide a piston and piston rod construction wherein a piston rod of adequate size and strength is substam 2 tially integrally bound to piston means which carry the usual sealing ring assembly comprising heavy rubber packing rings.

Still another object of the invention is to provide a slush pump piston construction such-that-j effective piston diameters may be easily increased or decreased according to pumping requirements,`

and a kindred object of the invention is to provide a piston construction-which may be easily assembled and disassembled as may be required/either` for the purpose of change in piston size or forthe purpose of replacing worn parts. v f

Other objects and various features of drawing andthe followingspecication wherein one embodiment of the invention is presentedby Way of illustration. In the drawing: v Y, Fig. 1 is aperspective View of a piston constructed and'mounted upon a piston rod .in a c.

power means by which the rod and its pistonare reciprocated. The piston-carrying end of the rod is reduced somewhat to provide an annular shoulder B `and to yield a reduced cylindrical pistoncarrying portion I0 upon which there is rigidly and permanently secured a sleeve I 2 of somewhat.

larger diameter thanthat of the main length vof the piston rod 5. The securing of the` sleeve 4I2 is accomplished by shrinking the same upon the. reduced rod portion I0 in a manner well known` in the metal working industry. For s-ome uses it is additionally important that a positive and permanent joint between the rod and the sleeve I2 be further assured, and this may be accomplished by weldings I3 adjacent the shoulder 8 and at the outer end of the rod Yportion Iii asy illustrated.-

Preferably, however, the inner end of the rod portion l and the corresponding end of the sleeve. I2 are provided with cooperating threads I4 for a short distance, such as about ten to twenty percent of their length or for a distance of about one to one and one-half inches of an eight inchrodk portion II). With such short threads I4, the expanded hot sleeve I2, when beingapplied, mayy be readily threaded into place before the shrinkage required by the operation occurs. When such threads I4 are employed, the Weldings I3 are seldom used. By means of such shrunk't the the iiivention will become apparent to those skilled-in this art upon reference to the accompanying pisannular integral hub I whose diameter is-sub- Y stantially the diameter of the smallest pump liner` in which the piston will be used. This hub VI5 constitutes a thrust-receiving ange or annular rib, and it provides on its opposite'sides annularv radially extending walls IB against which are received two opposed sealing ring assemblies, spaced as illustrated, by the hub I5. Thus, the sleeve I2 and the hub l5 provide a piston body to carry the sealing assemblies.

ring of a general configuration commonly employed on slushA pump pistons and more generally known in the Vtrade assembly asa rubber Ea-chrring 20 is provided with a conventionally flared vannularV rim 2| on its working face, such rim 2'I being compressible within the pump cylinder Yor liner( toV producethe required pumping seal. According to the present construction, each piston Vring 20 bears against a backing plate 22 F apertured to pass over the sleeve I2 and 'providing a wall 23 whose inward annular portion is rigidly bound against the corresponding radial wall VHi ofthe hub I5. Each piston ring 25 and its backing plate 22 are bound in the operative position illustrated by means of an elongated anchoring' nut' 24 which is mounted upon the sleeve l2 through the medium of threads 25, they respective packing ring 2U having its face oppo-v site fromy theV backing plate 22 engaged by a concave retainer plate 26 of suiciently smaller diameter not to interfere with the functioning of the rim 2| of the respective piston ring 20. Asl illustrated, thek internal diameter of each backing plate 22 is substantially the external diameter of the sleeve I2 at the ends of the respective threads 2.5, whereas the inner diameter of each piston ring 2B is somewhat greater in order to receive a reduced diameter extension 24a ofA its anchoring nut 24. The extension 24a thus provides an outer cylindrical surface 21 which receives the inner cylindrical wall of the adjacent rubber piston ring 20 and also receives the innermostedge of the respective retainer plate 2S.

. The retainer plate 26 is in each instance bound i against the piston ring 2U by a sloping shoulder 2li` formed by the portion of greatest. diameter of the anchoring nut 24. The angularity of the shoulder 28 is commonly in the order of 20 to A2E degrees with respect to the corresponding radius.

For the purpose of positively binding each backing plate 22, the inner end of the extension 24a of the respective nut 24 is beveled at an angle of about 45 degrees to provide a beveled thrust shoulder 30 whichrbinds against a correspondingly pitched face 3 I formed on the adjacent portion of the backing plate 22.. If deemed desirable, such backing plate may be packed against passage of fluid between it and the hub I5, this 'being accomplished, for example, by beveling itsl inner portion opposite the face 3I so as to provide a small annular pocket 32 in which is located a `circular rubber packing ring 33 which may be of circular crosssection and is compressed into packing form as the plate 22-is forced into Each assembly f comprises a heavy rubber sealing ring or piston the operative position illustrated. At the same time, sand which is contained in the fluid being pumped and which works past the piston rings 20 is successfully trapped in the annular space provided between the backing plates 22 and lying radially outside the hub I5, in all instances Where the plates 22 are vof larger operating diameter than the diameter of the hub I5. Thus, it is desirable in all slush pump installations to employ backing plates 22 and piston rings 29 of materially greater diameter than the diameter of the hub I 5V whereby to establish such annular sand-collecting space. It has been found that the functioningof this annular space to trap the sand which workspast the piston rings 20 very greatlyv reduces wear upon the piston rings 2t, the backineplatesZZ and the walls of the cylinder in which the piston operates, thereby very greatly prolonging the life of these portions of the equipment.

For the purpose of locating the anchoring nuts 24 in operative position, each Ymay Vbe provided with a fiber loelking ring "35 seated in an internal' annular groove 55 adjacent the outer 'end ofthe nut 24, whereby threads will be ycut in the iib'er ring 35 as it is turned into operative position. In order to insureV further against loosening of the anchoring nuts'24 during use, each is provided with an annular, thin integral rim'3I adjacent the outermostV end portion of the sleeve I2, this rim being formed by cutting an annular groove 38 in the end of the respective nut 2e. ToV cooper-A ate with portions ofthe rim 31, adjacent portions of the end of the' sleeve I2 are 'provi-'ded with notches 425 each of which, when the respective nu't 24 is serewedinto its operative position, a detent 31a is formed by striking `the adjacent portion o-f the riin-31 with a punch, the metal thus being depressed as illustrated. Such detents' may provide at only one position or at'a .plurality of positions as required'. By lifting the detent '31a with a toolwhen it is desired toV remove the Anut 24', Vthe respective notch 4t will be freed. This Vform of locating means' has the advantage of being formed with the nut turned up in its tightes't position, regardless of thev loca# tion of any portion of the rim 3l' and any par-Y ticular notch. 4e.

In employing the piston and piston rod construction of the' present invention, as will be apparent, a piston assembly may be built up of any required diameter greater than the minimum diameter dened by the hub I5. Suchr piston diameter will be determined by the diameter of the backing plates'22 and the rubber piston rings 25. When the parts 2i), 22 and 26' are positioned upon the respective 'end of the sleeve I2', the respective backing platev being against the hub I5, an anchoring nut 24 is readily turned up so that Yits beveled thrust' shoulder 39 engages the beveled face 3'! on the respective backing plate 22 and binds the latter against the adjacent radial wall I6 of the hub' I5. The beveled thrust shoulder 30 serves positively to center the respective backing plate 22, even though the diameter of the opening in Vthe respective plate 22 might be slightly greater than the Vdiameter of the sleeve I2 at this location. During thesame operation the beveled shoulder 28 engages the respective retainer plate 26 sor that it compresses to any required extent the rubberV retaining4 ring 2D. A detent 31a is then projected into one of the notches 40 through the application of a punch or similar offsetting tool to the adjacent portion of the rim 40. The same operations.Y are per-` formed at btlil'ends'- of 'the" piston. By reason of the described type of construction, the'rubber piston rings! 20', the backing Aplates Y22 and the concave retainer plates 26 are vreadily renewed or replaced-with parts ofY diilerent diameters, as has previously been indicated, the diameter of the' hub I5 vbeing no larger than Vthe diameter of the smallest* 'piston to be employed.' The two sealingr ringassemblies arranged as shown pro# vide fornormalreciprocating pump operations, the leading flared rim' 2| VVin. each instance hugf gingthe Vcylinder/or liner walls of the pump ac-Y cording to conventional practice. l I

Itis to be .particularly noted that all lthrust occasioned 'by vmovement of the pump rod 'in both directions 'of' reciprocation talce'n'by the hub lfandtransmittcd thence tothe sleeve I2, suchv thrust having been received by the hub' I5 from tli'ebacking fplates`22. Thus, the threads 25"'"are never required to take any great strain, inasmuchf as they have to resist onlythe trailing forces,`and these are inconsequential as compared withthe pumping loads and strains. The shrinkingof the sleeve I2v upon the reduced piston-carrying portion of the'rod,v together with the Weldings' I3 or threads I4,` positively prevent any dislodgment of the sleeve I2 with respect to the piston rod 5 and its end portion I0. Thus, the joint between` the piston assembly and the piston rod 5' is permanent and not subject to wear, no difliculties being encountered under loads` within the capacity of the rod 5 and its attachment by the threads 6 to'the'prime mover.

Further, in view of the increased diameter of the sleeve I2where the threads 25 are provided, land also in view of the elongationof the anchor'- ing nutsv24,l'wear and-loosening of the nuts 24l at the'vthreads '25 maybe entirely eliminated.' The ber locking rings 35 andthe detents 31a thor' ing plate-22 is cured by easyreplacement of the parts as heretofore described. v

Since variations of the invention herein disclosed' will, -no doubt, 'occur to others skilled in this art, it is intended to cover allmodiiications whichfall within the scope 'of the claims.'

I claim as my invention:

l. In combination in a piston rod and piston structure: a relatively elongatedpiston rod; 'a body member rigidly and permanently secured to and directly uponone endiof said rod substantially throughout the entire length of said body member by means of a welded, threaded, Vshrunk iit; and an annular hub rigidly and permanently secured to said body member and adapted to receive piston forming means against said hub.

2. In combination in a piston structure: a piston sleeve adapted to be secured to one end of a piston rod; an annular iiange rigidlyand permanently secured to said piston sleeve; a backin'g'plate adapted to be positioned against said ange; sealing means adapted to be disposed against said plate and to seal said piston'inl a cylinder; and means for removably'binding said plate and 'sealing means against said flange, whereby thrust upon said sealing means and plate is received by said flange and transmitted thereby to said sleeve and rod, said sleeve being provided with threads, and said'bindin'g means including a nut'threadeddon the threads of .saidv sleeve, the outer end Vof saidv nut being'provided with a thin rim adjacenty said sleeve,V and Vthe adjacentouter end-Y of said sleeve being provided with av notch into which a portion of'said thin rim-may be depressed to lock said nut against rotation on said sleeve. i e

' vv3.'In combination in a piston rodv and piston structure: a piston rod; a piston sleeve rigidly and ypermanently secured to one end of said rod; an annular radially extending rib rigidly and permanently attachedrto an intermediate portion'of said sleeve member and providing annular seats at'its opposite side; rigid backing plates respectively positioned-against said seats; sealing means respectively positioned against said backing plates and adapted to seal the piston in a cylinder during reciprocation therein, said backing plates and sealing means having greater external diameters than the external diameter of said annular rib, and providing a trap space around said rib and' between said 'rigid backing plates; and means for removably binding said plates and sealing means in said seats, whereby thrust upon said sealing means and backing plates is received by said annular rib upon reciprocation in either direction and such thrust is transmitted through said sleeve and rod, each of said means for binding said plates and sealing means against their seats being an elongated nut having a reduced portion passing centrally through said sealing means, the inner reduced end of each of said nuts bearing against the respective backing plate to bind the latter against said annular rib.

4. A combination as in claim 3 wherein the outer end of each nut is headed and provides a shoulder for binding its sealing means in operative position against the respective backing plate, a retainer plate being disposed abcut'the reduced portion of each nut and held bythe respectivenut head against the respective sealing means.

5. In combination in a piston and piston rod structure:V a piston rod; a sleeve member rigidly and permanently secured upon the end of said rod, the other end of said rod being adapted to be attached to means for reciprocating said structure; an annular rib rigidly and permanently connected to said vsleeve member and providing at one side a seat; a rigid backingl plate positioned against said seat; sealing means positioned against said backing plate and adapted to seal the piston in a cylinder; and means removably binding said backing plate and sealing means in said seat whereby thrust upon said sealing means and said plate is received by said rib, said backing plate and sealing means having greater external diameter than the external diameter of said annular rib, said rib accommodating back-V ing plates and sealing means of varying diameters for use in cylinders of varying diameters, said binding means including elongated nut means carried by said sleeve member and having a reduced portion projecting axially within and through said sealing means and bearing against said backing plate, thereby binding said backing plateupon'said seat ofl said annular rib.'

6. In combination in a piston' structure: a sleeve member adapted to be secured upon one end of a piston rod; an annular rib rigidly and permanently connected to a middle portion of said sleeve member and providing at each -side a seat; a rigid backing plate positioned against each seat; annular sealing means positioned against each backing plate, such backing plates andl sealing means having substantially greater external diameters than' said rib and thereby providing an annular space between said plates, and saidbacking plates supporting the annular' portions of said 4sealing means extending beyond ameter'toi; said ribf, and somewhat? Les said;srbxatheepentiens;einsame;sleeyeimember external diameteridf; therespectiveiseal Y 8.1 Av combination asini-claim 6; Whereinithe-inner;V ends 'of said nutsyand;the; innermost-vvalls of said backingl plates :are lconcentrically Sceyeledto 'center#,said'*backing'xplates .and to -force them against their seats on saidzannularsrlb.

1 9; A-combination .asin A,cla-im G fincludingepackving ameans @disposedbetweene:bevelediinnermost portions ,ioffsaid backing pla-tes and---thejointsfbetween said' rib and sleevemember.

A 101;gIni-combination..a pistcnqrod structureifan annular rib rigidly andfpermanently connectedto lsaid` piston rcdfistructurevande providingvatfone yside;,.,a seat; a;rigid,rrbacking platefpositioned against `said fseat fannularfesealing imeansfposi- Ationed against saidffbacking plate and supported by said backing plate, a portion of said rodfstrna- 4ture fbeyond l'said seat ,beingf'threaded :externally and having afsmallenexternalfdiameterthanthe internaldiamet'er'of -saidannular sealingmeans;

and. an yelongated Anut -threadedlyz mountedfupon said externally threadedA -f portionoff said;y rod structure t 4and fextending (throughf ,-,saidfqsealing means- -in engagement-f withthe inteinalgannular wall -thereofg-saidnutzbeing provided-with means forfretention-f ofy saidv sealing means.

' v11.-,A combination a'sin claim 10 Whereinaid 'elongated nut` extends into engagementwith said rigid ibacking plate fand rbinds 4:said fba'cking'plate =uponfsaids seat against-'saidannular rib.

-12: A combination fas; in 'claim 19 -wher einftne engaging portionsfoifsaidgbacking, plate and-v elongatednut are Arelativelyf inclinedtd xentergsaid backing plate.

-13; A'- combination :5a-s ln'v s Clairrn` i10 :including e packing fmeans 'd-ispased; between g-spacedggifnnermest .portions of-said loackingplatev and fribftovseal the j OinttherebetWeen.

: 14. In combination: ajpiston rod'structurefan annularange'rigidly and permanentlysecuredito saidrodestructure; a :backing plate adapted tol-oe positioned: against saidgflangeg v. sealirlgnr means adaptedito be disposed aeainstfsaidzplatefand to engager-thewalls of afcyliinder; andfzmeans-:for

removably; bindingv said plate iandfsealinggmea-ns ,against-.said iiange, wherebyizgthrust 1 nporrgsaid :sealngfmeans and ,plate is -received'loygsaidflange ',andv'transmitted therebyI to `said :rod structure,

saidirod vstructmre -being provided with :,thneads,

and said binding means including a nut threaded -endiof said nut being provided"with a 3thinr;im

-outer endy oi Vsaid rod structure beingfprovided with a notch1into.\yhich agi-portionof. said-thin v,ing:,:diameters,f said binding-r.

L8 rimzcmasifbei depressedftozleckesadanut aga-inst reta ien-.on saidfrodstrneuren Irz1 combination; apistorlf rodstructurean annular ribf reidlyand Apermanenfslasf connectedrte said zrcdzrvstructure Yand; :providing fat ionefside a seat;` rigid 'backineplate-positionedagainstsaid seatgksealing means pesitionedagainsizsaidzilack ine plate and :adaptedftofeneege cylinderrwalls; and means, removably bindingfsaid Iloaelaine-:plate and: fsealingrmeansin ;=..sai i,=- seat;l wherebxftnrusb lunen saidsealinefmeans rand-said v,plate i-sreeved having greater external diameters-than thesex- :ternal diameter ;of said annular; rib; :said ribpfaccemmodatne backing .plates-:and sealinazmeans er aryneidiametersoriuseimcylndersfnYanyea-na ncludne eloneatedgnut means-Carried:byffsaide mature v:and:having afreducedrtnbrton nroieetingaxially .within andfithrouehi said. seali'neimeansandhearine'eainst .r saidbackingnlatea therebyeb'rnding saidbackngplate upon saic`l-seat offfsaid; annular rib;

v Y16;; fIn` :v'ccmbnaton a f piston; .,.rodrv street-ure; an,v V.alinnlar radially extending; rile` rgidlyi and permanently; Vattachedtdv an intermediatefportionv of-:said 'rod' structureand providing annular seats at` its- I opposite sides; rigid backingi plates 4'respectively positioned against lsaidaseats: Sealing means `respectively positioned: against-backing -plates andadapted to'sealfthepistonin a cylinder duringreciprocation therein, -said ibacking' plates andsealing--meansv having greater.; externalediameters than --the external'. diameter of ':sadrannularrib, :and .providing aftrapY space ,around said .rib and doei-,Weensaidi rigid;` harald-11er;I plates: `:and meanszfolr :removablyzpbindng rfsaid t-plates.;` and sealing meansgin said-seataw-'Whereby thrust :.upon said: vsealingrrneansL Aand-l backing-g platessisfcreceivedby said annularf rib Mponfreciprocationfin .either gdirectionand` such Atln'ust; is; transmitted through:saidarodstructure, eaclrmeans -for Joinding said plates and.sealinggmeans:againstfftheir `seats;fleeing van elongated' nutghaving a reduced -portiorripassing centrally ,throught said sealing fmea'nsfthe inner 'reduced endgoffsaid riutsbearing against the respective :backing plate 'tobind the latter against said annular; rib.

Y 1'7.-r A combination fas; in? cla-im :16: wherein. the outerend Y"ruff-each wnut; is -head'ed'zand provides a shoulder -for; =bindingits sealing mea-nsr-in 'oper- Yative -position against `the respectivebaclgingzplate. a-retainerfplatezbeinggdisposed aboutl'fhe'gredud portion fof: each nut@ and heidiV bygthe respective nutfheaclagainst 'the'grespectiveasealingmeans.

v- `;18: In :combinations a fpiston ro df' structure :kan anmilarv ribg rigidly and permanently eonn'ectedlto a middleportion off said-pistoni rodustructureand 'providing at each-side aseat: arigidafbacking platee-positioned against eachffseat; annular, seal- 1,11'-means.psfmed-:aeainstfeach:backineplate. suchabacking -platesv and;l sealingfmeans; having substantially :greaterwexternal diametersfwthan vsaid rid, and: thereby providing-,anannularfspace betweensaid plates? and saidbackng v-platessupporting the annular, portionsffiof Vsaid ssealing means .extending Aloeyondsaid-rib; theportiensfef ,said -rod f .-.structure beyond L said ,seats being threaded .externally and Vhavingsmaller external diameters than, the internaLv diameters-,ofasaid ,annulargysealing-gv means; elongated rnutsJ- th'readedly .mounted upon said yexternal-ly threadedfportions.;of.,said rod vstructuref and `having,:outer surfaces extending within and frictionallyiengagthel innerl cylindrical, Walls. of said; .annular sealing means, said nuts being provided with headed portions whose external diameters are less than the diameters of said backing plates and sealing means; and retainer plates held by the headed portions of the respective nuts against the adjacent ends of the respective annular sealing means, said retainer plates being disposed around said outer surfaces of said nuts, and said retainer plates having external diameters greater than the external diameter of said rib and somewhat less than the external diameter of the respective sealing means.

19. In combination: a piston rod structure; an annular rib rigidly and permanently connected to a middle portion of said piston rod structure and providing at each side a seat; a rigid backing plate positioned against each seat; annular sealing means positioned against each backing plate, such backing plates and sealing means having substantially greater external diameters than said rib and thereby providing an annular space between said plates, and said backing plates supporting the annular portions of said sealing means extending beyond said rib, the portions of said rod structure beyond said seats being threaded externally and having smaller external diameters than the internal diameters of said annular sealing means; and elongated nuts threadedly mounted upon said externally threaded portions of said rod structure, and having outer surfaces extending within and frictionally engaging the inner cylindrical walls of said annular sealing means, said nuts being provided with headed portions whose external diameters are less than the diameters of said backing plates and sealing means, the inner ends of said. nuts and the innermost walls of said backing plates being concentrically beveled to center said backing plates and to force them against their seats on said annular rib.

20. In combination: a piston rod structure; an annular rib rigidly and permanently connected 10 to a middle portion of said piston rod structure and providing at each side a seat; a rigid backing plate positioned against each seat; annular sealing means positioned against each backing plate, such backing plates and sealing means having substantially greater external diameters than said rib and thereby providing an annular space between said plates, and said backing plates supporting the annular portions of said sealing means extending beyond said rib, the portions of said rod structure beyond said seats being threaded externally and having smaller external diameters than the internal diameters of said y annular sealing means; elongated nuts threadedly REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,216,218 Eddowes Feb. 13, 1917 1,796,415 Tyler Mar. 17, 1931 1,817,808 Eaton Aug. 4, 1931 1,955,157 Wayne Apr. 17, 1934 2,216,577 Stillwagon Oct. 1, 1940 2,315,012 Park Mar. 30, 1,943 2,321,160 Schnitzer June 8, 1943 2,443,110 MacClatchie June 8, 1948 

